kblack

2 years ago

The delivery van arrives at an office every day between 3 PM and 5 PM. The office doors were locked between 3:15 PM and 3:35 PM. What is the probability that the doors were unlocked when the delivery van arrived?
A. 5/6
B. 5/12
C. 1/3
D. 1/6

well we know there is a gap of 2 hours when the delivery van can come
that is the same as 120 minutes
we also know that out of that 120 minutes, 20 minutes the doors will be locked
so we minus this from the total hours it is open
120 - 20 = 100
this means out of 120 minutes there is 100 minutes where the doors will be open
which gives us the probability 100/120
after simplifying this you will get the answer 5/6
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